Treatment of keratins



a i T x Tn, Ff? ,v. 'l' bhtented Oct. 28, 1941 ing keratin such as hair and wogiand is parpou containing two r m r r a ve ha o n ticularly concernedTitli tY'athients for the apatoms, w by to form in or between the fibres plication of permanent set to such substances .5' e D bonds Containing a metal or for the removal of stress from materials made erganicg p The reatment with a reducfrom them, and for the treatment of keratininge m may e eff d a n m y r l containing materials in or before finishing opvatedtemp e e- Y rati 5 The disruption of the disulphide bond by re- Substances containing keratin are customarily duction in" this way relieves stress in the keratinsubjected to a-heat treatment, for example with Containing fi which Stress ay ve been steam or hot water for the application of a pers for instance, by p p y deforming he manent set to fibres or for the removal of stress r as means of a Curler and leaves h when inthe form of fabrics. Also, it has been fibres in a state such that further bonds may b proposed to treat wo l o hair wh i th caused to take place with the fibres in the destretched condition with boiling solutions of bi- O d d on by subsequent treatment with sulphite for the improvement of its appearance the metal Salvo! Organic p u 01 bon s and properties and subsequently to treat the wool e n S '-X-S- where X is a metal or oror hair with solutions of metal compounds such genie r ping- The fibres are stabilised in the as basic alum or with oxidising agents. Treatformation which they had during such treatment ment of wool or hair with boiling solutions of and-may t be caused to take on a P rmanent sulphites or bisulphites will cause disruption of g the disulphide bond tie-keratin and the formahebonds formed in the P e f the metal tion of S-NH bonds according to the following Or Organic compounds are resistant to steam n equations, where and 1391 hot water and consequently any set or formation resent the peptide and associated side chains of g en to -co taining fibres under treat- 1 mt ment wiilhbe retained subsequently by the fibres k I evenin e presence of hot water and steam. R-S-S--R+NaHSOs- Rr Theresistance of keratin fibres treated acimmediatew followed by guiding to the invention to deterioration by ala ine solu ions is considerably enhanced and SO3H+R NHWRSNHR +H2So3 consequently such fibres may be subjected to The reactions take place'with such readiness that treatment in alkaline liquors as in dyeing with the maXiImlm P b number of linkages vat or sulphur dyes without serious deterioration; sult and consequently a subsequent treatment In order that stress may be removed from kerawith a polyvalent metal compound, organic comtin containing fibres or fibrous materials, and a pound or oxidising agent will not result in any desired formation of th fibres or materials made appreciable rebuilding of linkages between the permanent, it is essential-that the treatment with peptide chains of keratin. the reducing agent to disrupt the disulphide The object of the invention is to provide a 40 bon'ds should precede as aseparate step the treatmethod of treatment of keratin containing subment with the polyvalent metal compound or stances for the removal of stress on the applica-' organic compound- If the reducing agent a tion of a set which maybe carried out at normal polyvalent metal compound or organic compound or raised temperatures and which will render are employed simultaneously, reaction may take the keratin containing substances resistant to place whereby the metal or 0rga,nic grouping deterioration by alkaline media and susceptible enters the disulphide bond, b t t reaction takes to dyeing without the use of mordants. place without change in the position of t bonds The invention consists in treating fibrous suband therefore without change in. the internal stance containing keratin, such as wool or hair, stress of the fibres or the formation of the fibres with a reducing agent at such concentration, pH 50. The-metal atoms introduced into the keratin TREATMENT OF knnn'rms John Bamber Speakman, Far Headingley, Leeds,

England I No Drawing. Application December 9, 1935, Se-

rial No. 53,688; In Great Britain December 10,

8Claims. (01. 167 871) N This invention relates to improvements in the treatment of fibres or fibrous materials containand temperature as to effect reduction and disruption of the constituent disulphide or cystine bond of keratin with the formation of sulphydryl groups and thereafter treating the substance,

while maintaining it in aform which it is desired tor'ender permanent, with a solution of a polyvalent metal compound or with an organic comfibres by the method ofthe invention, moreover, may be employed for attachment or those dye moleculesvwhich ordinarily require the use of a mordant.

'- Examples of suitablereducing agents which may be employed are sodium, ammonium or potassium bisulphite, sodium sulphide, sodium hydrosulphide, titanous chloride, cysteine hydrochloride, sodium hypophosphite, sodium thiosulphate, sulphurous acid, sodium hydrosulphite, ammonium, sodium or potassium sulphite, sodium dithionate and potassium metabisulphite, which may be used either alone or in combination with one another or with suitable media.

The reducing agent may be formed in situ as f by moistening the fibres with a small quantity of a solution of an alkali such as baryta which reacts with the fibre molecules to form a hydrosulphide, the concentration of which may be kept sufficiently high if the amount of solution employed is small.

Reducing agents as a whole, with the exception of those yielding S03 ions disrupt the disulphide bond of keratin with the formation of sulphydryl groups, although the quantity of disulphide bonds disrupted in any keratin-containing substance varies not only from one reducing agent to another, but also with the conditions of concentration, pH and temperature at which a-reducing agent is employed.

The reducing agents yielding S03 ions, as exemplified by sulphites, bisulphites and metabisulphites, efiect disruption of the disulphide bond of keratin by formation of RSNa and R-'SSO3H groupings at the boiling point, and acidsulphite solutions at pH 6 at temperatures as low as 50 C. effect the same disruption, but the formation of the groupings is immediately followed by the spontaneous formation of SNH bonds in these cases. Hence boiling solutions of reducing agents yielding S03 ions and acid sulphite solutions at pH 6 at 50 C. or above cannot be employed according to the invention. At temperatures appreciably below the boiling point and as low as 37 0. solutions of bisulphites and 1 meta-bisulphites can be employed to form sulphydryl groups from the disulphide bonds of keratin. Under such temperature conditions the disruption of the disulphide bond is attended initially by the formation of R.SNa and R SSOsH- groupings as in the case of the boiling solution but the formation of S-NH bonds does not take place. Removal of the bisulp'hite or meta-bisulphite from the fibres by treatment with alkali, aqueous acetone or by simple washing results in the conversion of the R-SNa and RSSO3H groupings into RSI-I and RP-SCH groups. Sufficient reducing agent is present to reduce the R-SOH groups to RSH groups. 4

While the treatment of the fibres or fibrous substances containing keratin with a solution of areducing agent may be effected within large limits of hydrogen ion concentration, it has been found that thereare two conditions under which optimum results are obtained, one when the solution in contact with the hair is at about pH 6 and'the other when a solution of pH 10 or above is employed.

At pH 6 the salt linkages between the peptide chain's'of animal fibres are most stable, relaxation in the strained fibres is delayed and more disulphide bonds remain in a state of strain for a'l'onger time. Since many reducing agents attack strained disulphide bonds more readily than unst'ral'ned bonds, the disruption of, the bonds is especially efiicient at pH 6.

At or above pH 10 the reducing agents are emcient because alkalies are able to attack disulphide bonds readily whether strained or unstrained, sulphydryl and sulphonic acid groups being produced by hydrolysis, and the latter groups are reduced by the reducing agent to sulphydryl groups. The sulphydryl groups are available for combination with the metal salt or organic compound.

The metal salts employed according to the invention may be the salts of metals other than the alkali metals, examples being salts of calcium, barium, zinc, copper or nickel. The salts may be oxidizing agents, for example, nitrates, or they may be used mixed with oxidizing agents, in order that formation of disulphide bonds from sulphydryl groups may proceed at the same time as the formation of SXS bonds, X being metal or an organic grouping, and thus reduce the time of treatment. Any desired concentration of the salt solutions may be employed, but 5% is a convenient concentration.

Where the solutions of reducing agents em ployed for disrupting the disulphide bonds are alkaline, the solutions of metal salts are desirably slightly acid in reaction, so that not only is the formation of further bonds in the fibre molecules assisted by the reduction of alkalinity in thefibres, but the probability of metal hydroxides or basic salts separating in reduced.

Forthe treatment of keratin-containing fibres or materials according to the invention, a solution of the reducing agent is applied to the keratin-containing :fibres as by immersion of the fibres, and then after sufficient time has been allowed for reaction with the fibres, for example about 15 minutes, the solution may be removed and the fibres may be washed, or the reducing agent completely removed by the use of an agent adapted to combine withit or otherwise render it inactive, or eliminate it; for example Where bisulphites are employed as reducing agents a 60% aqueous acetone solution may be employed to remove the agent. The washing operation or removal of the reducing agent is, however, unnecessary where the metal salt does not react with the reducing agent to form undesirable compounds, such as metal sulphides, which would stain or otherwise spoil the fibres. The fibres are then treated with the metal salt care being taken to ensure that the solution reaches all the fibres. The fibres may afterwards be washed. In place of a metal salt 'an organic compound such as phosgene may be employed to react with the reduced-fibres, when disulphide linkages containing an organic grouping will be formed. If the treatment is not intended to dissipate stress or impart a permanent set to deformed fibres but to form SX-S bonds for instance to impart resistance to alkali, the fibres may be treated with a solution containing a reducing agent and a metal salt, e. g. sodium sulphite and zinc sulphate.

In carrying the invention into eiliect according toone method as applied by Way of example to the permanent waving of human hair, the hair, after the usual shampoo, is treated With a solutionxof the reducing agent, e. g. sodium bisulphi'te, preferably of from 5 to 20 per cent. concentration, which may contain alcohol in suitable concentration, say 10%, to minimise oxidation of the bisulphite on exposure .to air, and which may be warmed upto about 40 'C. to assistpenetrationof the hair. The hair is wound on a curler and the .b-isulphi'te solution again applied, for example'by admitting it into atube surrounding the curler orby circulating it'inisome convenient zmanner about the curler.

P1 I Will! i ATlON F TEXTlLES 6t F355 '2 As: an. alternative method :.thehair. fmaylbe shampooe'mthen wound'on alcurlei'. in thedry-or. wet State and-"then have .the'isodiumbisulphite sol'utionapplied to it while on? the curler. i

In either case the solution is kept in contact with the hair 'for a: period of about fifteen minutes andthen withdrawn; The hair is thenztreated .withasolutionotanretal salt, e. g 5% copper water. containing 5 alcohol is prepared; the proportions of the two conipo'unds' being adjusted: to givepI-I "6;" ,The. solution is circulated about the hair;lwoun'd on a curler, by any convenient means for about minutes, being'maintained at from toz50lC. or'higheri l I W If it .I is not desiredto circulate the-reducing agent but merely'to apply 'itfto the .hair before or after winding it on a curler as byl-means of an absorbent wad, 'a'solution. at about pH SQis' employ'ed since thflhfllrl reduces .the pH to a value ofabout-ifi; A :solution may be prepared fromp'a half-*mo'lar solutionlof sodium sulphite by the addition of sodium -metabisu1phite' or other; acidic compound. When'the solution is applied to the hair it'rapidly decreases in alkalinity due'to-reaction with. thehair-and'the pH value becomes about. 6'; ;The hair; and the solution in. contact therewith are preferably maintained at 359-to C. or higher for'about fifteencminutes, as by applying the necessaryzheat to the curlersior by heating the hair by' a stream of hot. air-from a dryin'g apparatus, -evaporation or the solution be-x ing'prevented inthe latter; case by. covering the curlers or thewhole headzxvith a Water-impermeable'coven. 1:1 j HTreatmeritof thehair with a' metal isal'tithen follotvs as described above. A solution of; 5%. calcium or barium nitrate may beemp'loyed-as the. salt. solution .wherebyl both-1 disulphide bonds are formed bylr'oxidation of Z sulphydrylz groupsand .'1 Sf-BaS+. Tor ".-"-.S+'C a-Sfi. bonds :by combinationof such groupsywiththe metal. i

The-usual finlShlflgflipIOCCdllIE}iofiolfdlnary permanent Waving operations may then begivenm ."According to a. modification 'iof 2.:th'e-Ja'bove methodiwherein advantage istaken of the efiicient disruption'of disulphide bonds Qfkeratin in'ire-z: duc'ingl'solutions at pH 10 or higher, ahalf-molar solution: of sodiumi sulphiteiis brought to. about pH *1 l iorlhig'herby additiontof-sodium. carbonateorsodium meta silicate, or fa.6% sodium hydro'-. sulphide solution brought to pI-I 10 is employed. The solution is applied to the hair before'or. after win'dingbn-a; curler and in addition may be. cir-z culated about (the-hair on the curler; "A solution of an alkali, for. example a ,baryta solution at the specified pH; may also be employedfbeing'applied' to the hair in small: quantity. :1: The alkaliireacts with. the hair molecules andiiforms a hydrosulphide. Treatment is complete in about fifteen minutes at 30 C.

A fourth normal zinc sulphate solution containing an oxidizing agent, at an equivalent concentration, and preferably acidified, is employed to form -S-Zn-S- links and in addition disulphide bonds in the fibres and thus make the set permanent. The hair may then be subjected to; the finishing treatment usual info-permanent wavingo'perationsi .1 mSuccessful treatment offibre's andfibrous ma terials may-also beeffected at pH valuesyother thanipI-I' 6 and; pHlO-ll. Bisulphites'ior meta bisulphites, iforl. example, in concentrated solutionsi-at-taboutpHi are effective in'disrupting th'e'disulphidebonds of keratin at room tempe'ratur'e or above) Besides disrupting the disulphide bondslthe solution causes pronounced fibre swelling, being a. solution of .a weak acid. The effectiveness of the reagent is incr'eased'by in! cluding in solution with it an agent adapted to depress ionigttion of the reagentand increase the swelling fiect. Such agents areexemplified by theWater.:so1ublejalcohols, ethyl alcohol, glycerol, ethylene; glycol "and .ethyleneglycolmon'omethyleth'er. j i i f As an examplerof the method of treatingker atinl-containing fibres'xirifthis way, a 5 to 20% solution of a'l'bisulphite or'metal bisulphite containing: up to 45%"ethyl'alcohol is applied to unstrainedihair,andlallowedto reactfor about 15 minutes at room temperature or above. The swollen hair with disulphide bonds broken is then deformed'las' by'windingon a curler 'or forming thehair into curls or waves on the head; such deformation taking'place'without development of significant: internal stress. The configuration given to the hair is then made permanent by treatment witlr'a 5% solution of a metal salt suchas copper sulphate, .or'a solutioh'of .an organic compound;"with'or without an'oxidi'zing agent. The hair may then be g ven'the'usual finishing treatment of permanent waving operations.,.= :Inrthe above "case the hair may. equally be treated'with'the'bisulphite' or meta bisulphite solution after being deformed, as on curlers.

Accordingto a further modificationfor giving hair'agpermanentg wave or, set, th'e' hairis moistened with a solution'of a reducing agent and is formed into ;waves or curls on the head. To facilitate"manipulation of the hair a'thickening I agent maybe added to, the solutionof reducing agent,--for-example agar agar or kieselguhnin quantity suflicient to give the solution the con-' sistency of a paste. Wetting agents may also'be added. After treatment at'room temperature or above for 15 minutes, the hair, is treated with a solution of a me'tal salt as indicated; above, and given thegusual finishing treatment of'permanent waving'loperations. I

In" the application of the invention to fabrics containing, keratin, such as:wool, the usual crabbing and blowing operations for the removal or equalisingof stress in the fabrics may be dispensed with and a reduction treatment in the cold or warm solutions of reducing agents, such am as a 5 to 20% solution of alkali bisulphites, or a 0.6% solution of sodium sulphide'give'n in their place. The reducing agent by disrupting the disulphide bond in the wool molecule relieves stress inthe fibres. The fibres arestabilised by a sub-- sequent treatment with a 5% or other dilute somoval of distortion in knitted fabrics .of Wool arising from uneven strain on the yarn, by treatment of the fabric with a solution of a reducing agent,and. subsequent stabilising'by treatment with a metal salt solution or an. organic compound with or without an oxidizing agent.

Curled yarns for the manufacture of curl fab-. rics or artificial astrackan and Persian lamb fab-r rics may have a permanent set given to them by treatment of the deformed yarn with'a; reducing agent in the cold or warm state, followed by treatment witha solution of a' metal salt with or without an oxidizing agent, to: give permanence to the set.

The invention may be applied toimproving the resistance of fibres or fibrous materials containing keratin, such as fabrics or yarns, to deterioration by alkalies and alkali sulphide solutions, apart altogether from the application of a permanent set to the'fibre or relief of. stress in the fabric, by treatment with a reducing agent,

As the introduction of a metal atom or other grouping into the disulphide linkages of keratin may serve for the fixing ofdyes to the keratin molecules, keratin fibres or keratin-containing materials which have been treated with a solution of a reducing agent and then with a solution of a metal salt in the manner which has been described above in connection with the applica tion of a permanent set, the release of stress or.

the increasing of resistance of the keratin to deterioration by alkalies, may be subjected to dyeing without the need for a preliminary mordanting operation.

I claim:

lpMethod of permanently waving hair which comprises treating the hair for a period not ex ceeding 30'minutes with a solution of a reducing agent at a temperature appreciably below the boiling point and in the absence of amphoteric metals to effect reduction and "disruption of the disulphide or cystine bond of keratin of the hair with the formation of sulphydrylgroups and thereafter treating the hair while maintaining it in a curled or waved condition with a solution of at least one polyvalent metal compound whereby to form. sulphur bonds containing-a polyvalent metal in thehair'molecules while the hair is in the curled or waved condition;

2. Method of permanently waving hair which comprises treating the hair for a period not exceeding 30 minutes with an alkaline solution of a reducing agent at a pH of'at least and a temperature appreciably below thexboiling point and, in the absence of amphoteric metals to efiect reduction and disruption of the constituent di-- sulphide or cystine bond of keratin with the formation of-sulphydryl groups, and then while maintaining the hair ina curled or waved conditiontreating. 'it, with a 'solutionof at least one polyvalent metal compoundwhereby to form sulphur-bonds containing a polyvalent metal in the hair molecules while the hair is in the, curled or waved condition. :2

3. Method of permanently wavingv hair which comprises treating the hair for a period not exceedingj30 minutes with a solution of at least one compound of the group, consisting of acid sulphites of monovalentmetalsand radicals at a pH of about 4 and at a'temperature substantially below the :boiling pointof water-to reflect disruption ofthe constituentdisulphide or cystine bond .of keratinofthe hair with the formation of sulphy-dryl and sesulphonic acid groups, andthen while maintaining the hair in a curledor waved condition treating. it with a, solution of: at least one polyvalent metal compound, whereby to form sulphur bonds containing a polyvalent metal in the hairifmole'cules .while the hair isin the curled or waved condition. 1

'4. Method as claimedqin claim 1 wherein the hair istreated with-thereducing agent and, in the form. of; strands, is-then wound on curlers and treated with a solution-of at least one polyvalent metal compound while on the. curlers.

'53. Method as. claimed in claim2 wherein the hair is treated withthe reducing agent and, in the' form of strands, is then wound on curlers and treated with a'solution ofzat least one polyvalent metal compound while on the curlers.

v.6. Method as claimed inclaim 3 wherein the hair is treated with the acid, sulphiteand is then wound on curlers in the form of strands, and is treated with thesolution ofat least one polyvalent metal compound While on the curlers.

7."Metho-d of permanently waving hair which comprises treating the hair with an alkaline solution 'of an organic hydrosulphide, in the absence of amphoteric metals; to effect disruption of the disulphide bond of keratin of the hair and then while maintaining the hair in a curled or waved condition treating" it with a solution of at least one polyvalent metal salt whereby to form sulphur bonds containing a polyvalent metal in the hair molecules while the hair is in the curled or waved condition.

8. Method of permanently waving hair which comprises treating the hair for a period'not exceeding BOminutes with'an alkaline solution of a hydro-sulphide of an alkali metal, including ammonium, at a pH of at least 10 and at a temperature appreciably below the boil, in the absence of amphoteric .metals,'to effect disruptionof the disulphide bond of the keratin of the hair and then while maintaining the hair in a curled or waved condition treating it with a solution of at least one polyvalent metal salt whereby to form sulphur bonds containing a polyvalent metal in the hair molecules while the hair is in the curled or waved condition.

- :JOHNBAMBER SPEAKMAN. 

